1. Technical Field
This invention relates to a method of producing a mat comprising a filament loop aggregate and more particularly to a method of producing a mat suitable as porch mat, floor mat or the like comprising a filament loop aggregate formed from thermoplastic synthetic resin.
2. Prior Art
The method of producing such mat is well known, for example, from
(1) U.S. Pat. No. 4,351,683 and PA1 (2) U.S. Pat. No. 4,913,757.
However, according to the method as disclosed in (1), the filaments of one outermost row are cooled as they come into contact with a rotatable roll located to be exposed above the surface of cooling liquid and the remaining filaments are cooled by cooling liquid during formation of the filament loops. In other words, both the cooling conditions and the cooling timing are not even for all the filmanents and consequently there occurs a differential temperature among the filaments. It is therefore very difficult for this method to achieve uniform formation of the filament loops as well as adequate inter-filament setting. Moreover, this method is so arranged that the filaments of the outermost row come into contact with the lateral side of the rotatable roll to form successive loops lying fallen in a vertical plane which are often variable in shape and state.
According to the method as disclosed in (2) also, the filaments of one outermost row are cooled and successively formed into loops lying fallen in a vertical plane as descend onto a belt suspended above the surface of cooling liquid while the remaining filaments are cooled and successively formed into loops as they are submerged into cooling liquid. Accordingly, this method is necessarily accompanied with the problem similar to that encountered by the method disclosed in (1).
In conclusion, it is difficult for these methods of prior art to achieve a desired structural uniformity of the product since the loop forming conditions inclusive of the temperature condition are not uniform for all the filaments.
Based on findings that the filament loops may be formed under the conditions evenly set for all the filaments to achieve a structural uniformity and an improved quality of the final product, it is a principal object of the invention to provide a method of producing a mat comprising filament loop aggregate formed under the operative conditions evenly set for all the filaments.
It is another object of the invention to provide a method of producing a met with one or both of its opposite main surfaces being smooth, which presents appropriate elasticity, comfortableness to use and high durability.
It is still another object of the invention to provide a method of producing a mat having a high quality achieved by a uniform filament density of the filament loop aggregate.